From the state of the art chain guard systems are known, which are used in electric motor bikes, wherein the chain guard rotates in solidary manner with the entire system and wherein the assembly of several components is required due to the complexity thereof. Typically, the guard, crank and sprocket are joined together by tightening screw and nut systems and wherein the entire assembly is then threaded to the engine by means of a screw.
CN201756151U discloses precisely one of such chain guard systems which is directly tightened to the electric motor chassis. However, this document does neither anticipate nor gives clues about a chain guard system lock nut which is directly tightened to the bottom bracket as the one herein presented.
With the new generation of electric motors, manufacturers suggest that the sprocket should not rotate integral with the crank, which in this case involves a separation of the crank, guard and sprocket assembly.
With the technology presented in the present application, these problems are completely overcome.